An acid material (carboxylic acid or the like produced due to degradation of lubricant oil or hydrochloric acid, hydrofluoric acid, or the like which is produced when halogen ions which are produced through chemical decomposition of molecules that make up a refrigerant react with water) inside refrigerant piping in an air conditioner, a refrigerating machine, or the like causes a copper surface of the refrigerant piping (copper piping) to become corroded and copper ions are eluted in the lubricant oil. The eluted copper ions are precipitated and adhered, in a plating manner, on a portion which becomes high in temperature, such as a sliding portion (which is made of steel or cast iron which has high ionization tendency with respect to copper) of a rotary compressor (copper plating phenomenon).
Progress of the copper plating phenomenon causes a gap in the sliding portion to become smaller and thus sliding friction of the rotary compressor to be increased. In addition, when the copper plating peels off, interposition of the copper plating on the sliding portion is caused and thus abnormal wear of the sliding portion may occur or an expansion valve or the like in a refrigerant circuit may become jammed.
In order to solve the above problems, in the related art, a refrigerating machine is disclosed, in which refrigerant is subjected to compression or expansion such that movement of heat is performed and the refrigerating machine is equipped with a zinc or zinc alloy component that removes infiltrated or produced copper ions in the refrigerant circuit (for example, see PTL 1).